Combined protractor, adjustable tall square, and rule



Aug. 11, 1925.

G. M. LARSON COMBINED PROTRACTOR, ADJUSTABLE l1-SQUARE, AND RULE Filed Jan. 26, 1924 glinmugnu HUMLUMMLLZL;

67.1% Lasom yPatented Aug. l1, 1925.

UNITED STATES PrnEN'r` OFFICE.

Guerin. LAnsoN, or numana, nmnnso're.. connnmn Pnoruc'roa, ADJUSTABLE 1- saunnn, Annarita.

Application Med January 28, 1924. Serial No. 688,775.

To all whom it may omwem.

- Be it known that I, GUs'r M. .Lancom a f citizen ofthe United States, residing at Munger, in the county of St. Louisand State of Minnesota., have invented certain new and useful; Improvements in Combined able T-square, protraetor and rule, the con- Protractors, Adjustable T Squares, and Rules; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to whichI it appertainsl to make and use thesame.

The present invention has relation to drafting vinstruments and has for its object to provide in a single structurean adjust-A struction being such as to admit of the in! strument being formed from metal, such as steel. c

Other'objects and advantages will be apparent and suggest themselves as the nature of the invention .is understood. y

While the drawings illustrate an embodiment of the invention it is to be understoodthat in adapting the same to meetdifferent conditions and requirements, various changes in the form, proportion and minor details of construction may be resorted to without departing from the spirit of the invention.

Re erring to the accompanying drawings form g a part of the application:

Figure 1 is a top plan view of a drafting instrument embodying the invention, an intermediate portion of the bladel being broken away,

Figure 2 is an edge view of the instrument,

Figure 3 is a sectional view on the line .3-3 of Figure 1, looking in the direction of the arrows,

Figure 4 is a detail sectional view on the line 4-4 of Figure 1, and Y l Figure 5 is a sectional detail view on the line 5-5 of Figure 1.

Corresponding and like parts are referred to in the following description and desig.- nated in the several views of the drawings by like reference characters.

Thev instrument comprises a blade 1 andl a orosshead 2 at one end of the blade and pivoted thereto by means of a rivet 3 or 'other .preferredfastening. Thel blade 1 is extended outwardly from its pivot connectlonwith the head 2, as indicated at 4, and terminates in a point 5 which functions as an indicator. protractor 6 is formed with the crosshead 2 and is suitably calibrated for nicety of adjustment in the laying out of angles. The protractor 6 is formed with 4a slot 7 in-which operates a fastening 8 which may be tightened to secure the blade 1 1n the required adjusted position with .reference to the head 2 and p-rotractor 6. The fastening 8 includes a thumb nut 9, whereby provision is had for securing the blade in the required adjusted position. The head 2 and protractor 6 constitute parts of a single `piece of sheet metal and the outer or for.

ward edge of the head 2 is turned downwardly, as indicated at 10, to provide a stop to engage the edge of a drawing board or other article. Lugs 11 are partly cut from the bent edge portion 10 and occupy a position in the plane of the head and protractor to engage the top side of the drawing board 4or like article to give proper support and prevent tilting of the instrument when in service. The blade 1 is suitably graduated along an edge whereby it may be used in a manner similar to a ruler.

What is claimed is:

1. A drafting instrument of the character specified, comprising a blade pointed at one end to provide an indicator, a crosshead pivoted -to the blade a short distance from its pointed end, a protractor formed as a part of the crosshead and with which the pointed end of the blade coacts, said protractor having a slot concentric with the pivot, a fastening carried by the pointed end of the blade and operating in the slot ofthe protractor to secure the blade in the required adjusted position, a stop formed on said cross head, and lugs extending from said cross head.

2. A drafting instrument comprising a blade having one end pointed to provide an indicator, a crosshead nivoted to the blade a short distance from its pointed end and having its forward edge portion bent downwardly -to provide a stop, lugs formed by port-ions of said downwardly bent edge portion partly cut therefrom and disposed in f the honglto prevent tilting of carried by thjepohlted-cnd of thefbludound the nst-runwntwhen in use, a protractor operating in the slot of the protractor.

formed integral with said cross hond and in In testimony whereof I affix my signature.

which is provided a curved slot concentric 5 with the pivot of the blade, and a fastening GUST M. LARSON. 

